CN1288644A - TDMA-TDD/FDD radio communication system and channel selection method and apparatus for such a system - Google Patents

Abstract

A TDMA radio communication system combining time division and frequency division duplexing. It comprises a first base station transmitting in first downlink frames (118,120) on a first carrier Frequency (FTX) in a first frequency band and receiving in first uplink frames (122) not overlapping in time with the first downlink frames (118,120) on a second carrier Frequency (FRX) in a second frequency band not overlapping in frequency with the first frequency band. The system also includes a second base station having a coverage area that partially overlaps the first base station. But is geographically separated from the first base station so as not to interfere with the reception by radio terminals on other base stations from transmissions from one base station. The second base station transmits in a second downlink frame (128) at a second carrier frequency and receives in a second uplink frame (124,126) at the second carrier frequency without time overlap with the second downlink frame. The first and second link frames are offset so as not to overlap in time. A network controller synchronizes transmissions from the first and second base stations.

Description

Time Division Multiple Access-Time Division Duplex/Frequency Division Duplex Radio Communication System and Channel Selection Method and Apparatus for Such System

The present invention relates to the field of mobile radio communications, in particular to a system for realizing time division multiple access by combining time division duplexing and frequency division duplexing. The invention also relates to a dynamic channel selection method and device for radio terminal control of the system.

The "Digital Enhanced Cordless Telecommunications" system (DECT) standard is developed by the European Telecommunications Standards Institute and is an example of a system for radio communication using TDMA-TDD (Time Division Multiple Access - Time Division Duplex). In DECT, transmissions are synchronized between all base stations, ie all downlinks are transmitted during the first 5 milliseconds of a frame and all uplinks are transmitted during the second 5 milliseconds of the frame. On a TDMA-TDD carrier frequency, the first 5 milliseconds are dedicated to 12 downlink time slots and the second 5 milliseconds are dedicated to 12 uplink time slots, enabling the downlink of the same two-way connection with one carrier frequency and uplink communication.

The known TDMA-FDD (Time Division Multiple Access-Frequency Division Duplex) system combines downlink transmission with uplink reception by the mobile station and simultaneously in the radio base station performing two tasks on different carrier frequencies and at different times separate. GSM and D-AMPS systems are an example of TDMA-FDD systems.

Both TDMA-TDD and TDMA-FDD systems have their advantages and disadvantages. WO97/21287 (ADVANCED MICRO DEVICES) describes an example of an attempt to combine the advantages of TDMA-TDD and TDMA-FDD. In this TDMA-TDD/FDD system, uplink and downlink transmissions between a radio base station (BS) and a mobile station (MS) are separated in time and frequency. In TDMA-FDD, uplink and downlink transmissions use separate frequency bands, but in TDMA-TDD, uplink and downlink use separate time intervals. However, the disadvantage of the system described in WO 97/21287 is that by switching the uplink transmission to a frequency band separate from the downlink transmission frequency band, each frequency band will only be used 50% of the time, which is a huge waste of valuable spectrum resources.

The primary object of the present invention is to provide a TDMA-TDD/FDD system with more efficient spectrum combination, which allows uplink and downlink transmission of asymmetric traffic, for example, the downlink has more traffic, such as Internet connection may be required.

Another object of the present invention is to provide such a spectrally efficient TDMA-TDD/FDD system which allows the implementation of mobile station controlled dynamic channel selection (DCS).

Another object of the present invention is to provide such a spectrally efficient TDMA-TDD/FDD system which allows communication over fixed long distance RLL (Radio Local Loop) connections in a cost effective manner.

These objects are achieved by the features described in the claims.

Briefly stated, these and further objects of the present invention are achieved by providing two sets of radio base stations in a synchronous TDMA-TDD/FDD system using two frequency bands. A first group of base stations uses available frequencies some of the time and a second group of base stations uses available frequencies the rest of the time.

In one embodiment of the invention, half of the communications use the first set of base stations and the other half of the communications use the second set of base stations. There is a time offset between the two base stations that allows downlink and uplink transmission at all times on all frequencies, but not simultaneous transmission and reception at the same unit (eg, same BS or MS). In this embodiment, the first frequency band is always used for uplink transmission and the second frequency band is always used for downlink transmission. In this embodiment, two sets of base stations have partially overlapping radio coverage, but are geographically separated to avoid base stations in one set interfering with reception of the other set during transmission.

In another embodiment of the invention, half of the communication also uses the first set of base stations and the other half uses the second set of base stations. However, in this embodiment, the first group uses some time slots on a carrier frequency in the first frequency band for uplink transmissions, while the second group uses some time slots on a carrier frequency in the second frequency band . This allows downlink and uplink transmission on all frequencies, but avoids simultaneous transmission and reception on the same unit, (eg same base station and mobile station). In this embodiment, a first time interval is always used for uplink transmission and a second time interval is always used for downlink transmission. This arrangement facilitates asymmetrical use of frequency bands, which is explained further below.

In another embodiment, the invention is used for fixed connections in an RLL system, for example, between network controllers and buildings over relatively long distances on the order of 20 km.

In another embodiment, dynamic channels are used by listening at the mobile station not only to downlink time slots not used by the mobile station itself as in the prior art, but also to the downlink time slots of another set of base stations Selection (DCS), so when channel switching and initial selection for a call, a channel belonging to any group of base stations can be selected.

An important technical advantage of the present invention is that by utilizing the unused 50% of the radio base station available when a two-way (duplex) communication channel uses only 50% of the uplink carrier frequency and 50% of the downlink carrier frequency time, providing the spectral efficiency of a synchronized TDMA-TDD/FDD system.

Another important technical advantage of the present invention is that it utilizes the previously unutilized 50% of the uplink and downlink carrier frequency availability by delaying a portion, for example, 50% of the transmission, thus satisfying the uplink requirement of always using one frequency band. link and downlink of another frequency band as required by any specifications.

Yet another important technical advantage is that, in the absence of the aforementioned specification, the unused 50% of the time previously available on uplink and downlink carrier frequencies does not require frequency bands to be assigned to uplink and downlink carriers, respectively. Instead, the link utilizes the first time period assigned to the downlink and the second time period assigned to the uplink. The advantage of this designation is that asymmetric uplink and downlink transmissions such as those required for Internet connections can be used. Any multi-channel usage, as an added advantage, employs frequency hopping between slots of a multi-slot burst.

Another important technical advantage of the present invention is to combine the low-cost advantage of TDMA-TDD with the long-distance mobile phone of TDMA-FDD. This is of particular interest in RLL, since the longer distances from one network controller to remote base stations can be handled by TDMA-TDD/FDD radio connections, while the local short-range radio connections between base stations and mobile stations can be handled using traditional TDMA-TDD, but not excluding TDMA-TDD/FDD as another possibility.

Another important technical advantage is that the TDMA-TDD/FDD system of the present invention firstly provides the advantages of TDMA-FDD such as long-distance radio connection in mobile phones without frequency planning, because the TDMA-TDD/FDD system of the present invention The FDD system, in one embodiment, uses the mobile station to perform dynamic channel selection, which is common to the TDMA-TDD system, but has not been used in the TDMA-FDD system before.

Another advantage of the invention is that it allows two operators to operate on the same frequency band. Different operators of previous TDMA-FDD systems were restricted to work on different frequency bands.

The invention, together with objects and advantages thereof, will be best understood from the following description when read in conjunction with the accompanying drawings.

Figure 1 schematically shows a cellular mobile radio communication system;

Figure 2 schematically shows the use of carrier frequencies in a TDMA-TDD system;

Figure 3 schematically shows the use of two carrier frequencies in a TDMA-FDD system;

Fig. 4 schematically shows the use of two carrier frequencies in the prior art TDMA-TDD/FDD system;

Figure 5 schematically illustrates the use of two carrier frequencies according to an embodiment of the present invention;

Figure 6 schematically shows the use of two carrier frequencies in an embodiment of a full-rate channel implemented in a GSM system modified according to the invention;

Figure 7 schematically illustrates the use of two carrier frequencies according to another embodiment of the present invention;

Figure 8 schematically illustrates the use of two carrier frequencies according to an asymmetric embodiment of the invention;

Figure 9 schematically illustrates the use of two carrier frequencies according to another embodiment of the present invention:

Figure 10 schematically shows a cellular mobile radio communication system with radio connections between a network controller and a radio base station;

Fig. 11 is a flow chart illustrating the dynamic channel selection method suitable for the TDMA-TDD/FDD system working according to Fig. 5 embodiment;

Fig. 12 is a simplified block diagram suitable for implementing the dynamic channel selection method of Fig. 11;

Fig. 13 is a flowchart suitable for the dynamic channel selection method of the TDMA-TDD/FDD system of work according to Fig. 7 embodiment; With

FIG. 14 is a simplified block diagram of a mobile station suitable for performing the dynamic selection method of FIG. 13. FIG.

The terminology of prior art TDMA-TDD and TDMA-FDD systems is inconsistent. The following terms are used in the description below:

A downlink frame is a collection of consecutive time slots (bursts) transmitted from a base station.

An uplink frame is a collection of consecutive time slots received by the base station.

A duplex frame is a collection of downlink and uplink frames.

Figure 1 schematically shows a part of a cellular mobile radio communication system. A network controller, eg a mobile services switching center MSC, and two geographically separated base stations BS1 and BS2 in the same area (radio coverage partially overlapping). The base stations BS1, BS2 are in radio communication with the respective mobile stations MS1 and MS2. The main concern of the present invention is the nature of the radio connections between these base stations and mobile stations.

Figure 2 schematically shows the use of carrier frequencies in the frequency band used by prior art TDMA-TDD systems. A base station, such as BS1, transmits on the carrier frequency F in downlink to the mobile station MS1 in the time slot marked TX in the downlink frame 100 . The mobile station MS1 transmits uplink to the base station on the same carrier frequency in the time slot marked RX in the uplink frame 102 (a time slot marked RX indicates that the base station is operating as a receiver during that time slot). The downlink frame 100 and the uplink frame 102 together form a duplex frame. Downlink frame 104 is the first part of the next duplex frame in which this pattern is repeated. Note that the time slots TX and RX belonging to the same duplex channel have the same position with respect to the start position of their respective frames (downlink and uplink frames).

Figure 3 schematically shows the use of two carrier frequencies in two frequency bands as used in a prior art TDMA-FDD system, such as a GSM system. In this case, downlink transmissions are separated from uplink transmissions by performing two tasks on different carrier frequencies FTX and FRX. A duplex connection is made up of repeated downlink and uplink time slots TX, RX on frame pairs (106, 112) (108, 114) (110, 116). Note that uplink frames are delayed relative to downlink frames (3 slots in CSM) compared to transmission and reception at the base station.

Fig. 4 schematically shows the use of two carrier frequencies in two frequency bands in a TDMA-TDD/FDD system in the prior art. Because the TDMA-FDD method is adopted, the downlink transmission and the uplink transmission are separated by performing two tasks on different carrier frequencies FTX and FRX. However, this combined system is also similar to a TDMA-TDD system, since the downlink and uplink frames are also separated in the same way as in a TDMA-TDD system. A duplex frame is composed of a downlink frame 118 and an uplink frame 122 .

It can be seen from FIG. 4 that the prior art TDMA-TDD/FDD system only uses 50% of the time of each carrier frequency. During idle time, the base station neither transmits nor receives, which is inefficient.

Fig. 5 schematically illustrates the use of two carrier frequencies in two non-overlapping frequency bands according to an embodiment of the present invention. As in the TDMA-TDD system of Figure 4, the downlink frames 118, 120 and the uplink frame 122 are assumed to comprise duplex connections BS1-MS1. However, according to the invention, the idle period of FIG. 4 is used by another base station, for example base station BS2 in FIG. 1, to provide other connections, such as a BS2-MS2 connection. These are represented by dashed downlink and uplink frames 128, 124, 126, respectively. In this figure and the following figures, the connection BS2-MS2 uses the same time slots as the connection BS1-MS1. However, any other time slot may also be used for the connection BS2-MS2. Note also that base station BS2 still transmits on frequency FTX and receives on frequency FRX, but the transmission (and reception) is delayed by half a duplex frame compared to base station BS1. The same principle can be used for other carrier frequencies belonging to the two bands of frequencies FTX and FRX. Thus, the present invention fills the idle period in the prior art system of FIG. 4 by providing two sets of synchronized base stations and time shifts for transmission (and reception) of that set. Synchronization and time shifting are controlled by the network controller MSC of FIG. 1 . Base stations BS1 and BS2 have partial radio coverage, but are sufficiently separated geographically so that reception of mobile stations by one base station is not interfered by transmissions by mobile stations of other base stations. Since the frequencies FTX and FRX are different (eg 45 MHz apart in the GSM system), a separation of around 10 meters is usually sufficient. This embodiment of the invention also restricts downlink transmissions to one frequency band and uplink transmissions to another frequency band, which is often required in the regulations of some countries.

Figure 6 schematically shows the use of two carrier frequencies in two non-overlapping frequency bands in an embodiment implementing a full rate channel in a GSM system modified according to the invention. In order to separate the base station's transmission and reception in time and frequency, the delay between uplink and downlink frames has been increased to 3-8 time slots. In addition, the "idle" period is filled by a second base station whose transmission and reception are synchronized with the first base station but delayed by one downlink frame relative to the first base station. A full rate channel is implemented by using two time slots in each downlink and uplink frame. In this embodiment, two hours in each downlink and uplink frame are allocated to the full rate channel. In the embodiment shown in FIG. 6, the two time slots are consecutive. However, this is not required. They can also be separated by 1, 2 or 3 slots.

Fig. 7 schematically shows the use of two carrier frequencies in two non-overlapping frequency bands according to another embodiment of the present invention. In the TDMA-TDD system of FIG. 4 and the embodiment of FIG. 5, the downlink frames 118, 120 and the uplink frame 122 are assumed to comprise a duplex connection BS1-MS1. A duplex connection BS2-MS2 is provided by downlink frames 130,132 and uplink frame 134. However, in this embodiment, downlink and uplink transmissions are not restricted to separate frequency bands. Instead, two sets of synchronized (synchronized by the MSC) base stations transmit and receive simultaneously. Note that each carrier frequency is used for downlink and uplink transmissions (thus, they are labeled F1 and F2 instead of FRX and FRX as in Figure 5). This embodiment can be characterized as such a sentence: "all base stations "do" the same thing (send or receive) at the same time", while the embodiment of Figure 5 can be characterized as such a sentence: "all base stations do "on the same frequency band" "Same thing (send and receive)". Furthermore, this embodiment does not require geographical separation of the base stations BS1 and BS2.

Figure 8 schematically illustrates the use of two carrier frequencies on two non-overlapping frequency bands according to an asymmetric embodiment of the invention. An analysis of the expression "all base stations "do" the same thing (send or receive) at the same time" reveals that in this embodiment it is not actually necessary for the downlink frames to have the same duration as the uplink frames. This leads to the possibility of an asymmetric embodiment of the invention, as shown in FIG. 8 . In the embodiment of FIG. 8, only two available carrier frequencies are reserved for two duplex connections, BS1-MS1 and BS2-MS2, respectively. The two connections are asymmetrical in the sense that downlink frames are much longer than uplink frames. This asymmetry is useful, for example, when a mobile station is connected to the Internet. This Internet connection is characterized in that much more data is sent to the mobile station than received from the mobile station. An asymmetric connection can be established by the network controller MSC by reserving a carrier frequency from each frequency band. Note, however, that if such an asymmetric connection is established, the other connection on the same carrier frequency (which occupies idle periods) must also have exactly the same asymmetry (because it must "do the same thing at the same time ( sent or received)”).

Fig. 9 schematically illustrates the use of two carrier frequencies in two non-overlapping frequency bands according to another embodiment of the present invention. In this embodiment, a third group of base stations is added, including a base station BS3. Each group of base stations transmits on frequency FTX and receives on frequency FRX. In fact this embodiment illustrates that the basic idea of the invention can be implemented with more than two groups of base stations. Since one of the advantages of the present invention is that several operators can use the same frequency band, this embodiment is attractive if two or more operators are allocated to the same frequency band. Another embodiment of the present invention is that if the business volume of one operator is larger than that of another operator using the same frequency band, at this time, the first operator can use two sets of base stations, while other operators only use one set base station.

FIG. 10 schematically shows a cellular mobile radio communication with a radio connection between a controller and a radio base station. As explained earlier, according to the invention, reception and transmission in the base station do not take place simultaneously, thus greatly saving the cost of the base station, since it is technically simpler to separate transmission and reception in time than in frequency much. However, if simultaneous transmission and reception are necessary, as in the case of network controllers, it is possible (at the expense of increased cost) to employ frequency division in the controller using filters and directional antennas. In Fig. 10 the radio base stations BS1, BS2 communicate with respective mobile stations MS1, MS2 using different offsets. The network controller MSC transmits like a mobile station, thus enabling the controller to transmit and receive simultaneously.

In another embodiment, not shown in Fig. 10, there are two controllers, each associated with a radio base station BS1, BS2. This embodiment can be used in situations where there are two independent operators operating in the same geographic area. The present invention requires them to synchronize their systems, but still each run their systems completely independently since they are each allocated 50% of the time available to the frequency band.

The prior art radio system of Fig. 2 can adopt dynamic channel selection, can refer to: 11.4 of ETSI ETS300 175-3 of DCS.State of the art DCS for DECT TDMA-TDD: "Radio Equipment and Systems (RES); Digital European Cordl ess Tel ecommunications (DECT) Common Interface Part3: Medium access 1ayer" and AnneX E of ETSI ETR 310: "Traffic capacity and spectrum requirements for multi-system and multi-service applications co-existing in a common frequencyband". The selection of the traffic channel is performed by the mobile station. For a symmetric duplex channel, the first half of the frame (5 milliseconds) is used for downlink time slots and the second half of the frame (5 milliseconds) is used for uplink time slots. For a duplex channel, each downlink time slot is paired with an uplink time slot, both operating on the same carrier frequency. The mobile station selects the least interfering channel (duplex pair) from all available channels for each new call or handover. During this process, the mobile station only makes measurements in the downlink frame. The reason why measurements only need to be performed on the downlink is that for a duplex connection, the corresponding uplink is only used together with the downlink. Therefore, there is a high correlation between the measured downlink quality and the quality of the corresponding duplex connection, which is sufficient to estimate the duplex connection quality. According to the present invention, for TDMA-TDD/FDD , the downlink and uplink frames not only use different parts of the duplex frame (front and back halves), but also use different carrier frequencies (see Figure 5). This change does not require a change to the basic DCS steps described above. As long as the mobile station only has access to synchronized base stations (only one set of base stations) with the same time offset, it is still sufficient to use only downlink frames as quality estimation for duplex channels.

However, for the TDMA-TDD/FDD system of the present invention, two carrier frequencies are only used for half the time for each group of base stations. Therefore, as described above for FIG. 5 , two groups of base stations can be defined with a half-duplex frame relative offset (or, as shown in FIG. 9 , 3 groups of base stations with a 1/3 duplex frame relative offset). In this way, the carrier frequencies FTX and FRX are fully utilized. As long as each mobile station considers access to only one of the base stations, the basic DCS steps described above still apply (reasonable restrictions on the application of RLL). However, if the mobile station is to access all base station groups and be able to perform handover between base stations, the above DCS steps must be modified. A mobile station is always locked to a base station belonging to one of the groups of base stations. In order to handover or set up a call to a base station belonging to another group, the mobile station has to scan the downlink with the offset as defined for the new group. The change in DCS is then that the mobile station must scan the receive carrier frequency not just for half-duplex frames, but for the entire duplex frame.

FIG. 11 is a diagram illustrating a dynamic relative selection method applicable to a TDMA-TDD/FDD system operating in accordance with the embodiment of FIG. The procedure starts at step S1. Step S2 measures channel quality on the downlink belonging to a group of base stations. In step S3, offset information on group 1 is received by the mobile station. Step S4 measures the channel quality on the downlink belonging to the group 2 base stations. Offset information on group 2 is received by the mobile station at step S5. Step S6 determines which downlink channel has the least interference on which frequency, step S7 locks to the corresponding channel and adjusts the timing according to the offset to the corresponding set of base stations. Step S8 ends.

Figure 12 is a simplified block diagram of a mobile station MS suitable for carrying out the dynamic channel selection method of Figure 11 . The control unit CU controls the transmitter TX and the receiver RX via the switches SW1, SW2, and the control signal C controls the switches SW1, SW2. The switches SW1, SW2 connect their transmitter TX and receiver RX to the control definition CU and the antenna A. When the mobile station MS is not transmitting, it measures the interference level and slot timing (from both sets of base stations) on the carrier frequency of the downlink frequency band. It also continuously updates the memory unit CH in which the least interfering channel and its timing channel identity are stored. The control unit CU usually consists of a microprocessor or a combination of microprocessor signals and a corresponding control program P1.

For the embodiment of FIG. 7, the mobile station does not have to take into account the offset between the different sets of base stations with respect to the DCS. However, since there is now a simultaneous downlink on two frequencies F1 and F2, it has to measure the channel quality on two downlink frequency bands instead of one. It must also be able to transmit and receive on any of these bands, since it can lock to a base station of any set.

FIG. 13 is a flowchart of a dynamic channel selection method applicable to a TDMA-TDD/FDD system operating in accordance with the embodiment of FIG. 7 of the present invention. The procedure starts with step 10. Step 11 measures, at the mobile station, the channel quality of downlink frames belonging to a first group of base stations transmitting in a first frequency band. Similarly, step 12 measures the quality of downlink frames at base stations belonging to a second group transmitting in a second frequency band. Step S13 determines which downlink channel has the least interference, and step S14 locks onto the corresponding channel. Step S16 ends the program.

FIG. 14 is a simplified block diagram of a mobile station suitable for implementing the dynamic channel selection method of FIG. 13. FIG. The block diagram is similar to the block diagram of FIG. 12 . The main difference is that the control unit CU executes another control program P2 to measure interference in time slots on both frequency bands. The control unit CU also controls (with control signals C1 and C2) the transmitter TX and the receiver RX to transmit and receive on any one of the frequency bands according to the currently selected channel.

Those skilled in the art will appreciate that various modifications and changes can be made to the present invention without departing from its spirit and scope as defined by the claims.

Claims (18)

1. a TDMA radio communications system that makes up time-division and Frequency Division Duplexing (FDD) comprises

One first base station, has first radio coverage area, on first carrier frequency in first descending chain circuit frame emission and on second carrier frequency, receive in first uplink frame, first uplink frame and described first descending chain circuit frame are not overlapping in time, second carrier frequency is different from first carrier frequency, and described system is characterized in that comprising:

One second base station, it has one second radio coverage area, in second descending chain circuit frame emission on first carrier frequency with on described second carrier frequency, receive in second uplink frame, not overlapping on second uplink frame and the described second down link frame time, described second radio coverage area part is overlapping with described first radio coverage area, and separate mutually on described second base station and the described first base station geography, to avoid disturbing on other base stations reception from radio terminal from the transmission of a base station;

A network controller is synchronously from the transmission of described first and second base stations and will be from the transmission of second base station descending chain circuit frame of transmission skew with respect to described first base station.

2. the system of claim 1 is characterized in that: each descending chain circuit frame has a time slot with a join dependency connection.

3. the system of claim 1 is characterized in that: each descending chain circuit frame has 2 time slots with a join dependency connection.

4. the system of claim 1 is characterized in that: mobile radio terminal monitoring channel quality and from the skew of the descending chain circuit frame of two base stations is used for for call setup and switches the dynamic channel of carrying out mobile radio terminal control selecting.

5. the system of the arbitrary claim in front is characterized in that:

Described first base station belongs to one group and has a predetermined base station regularly that sends;

Described first frequency belongs to first frequency band that use the base station in two groups of base stations; With

Described second base station belongs to one group of second base station, it and described first group of base station synchronised, but with respect to descending chain circuit frame of transmission timing slip of described first group of base station:

Described first frequency belongs to second frequency band that is used by the base station of two groups of base stations, and described second frequency band and described first frequency band do not have frequency overlap.

6. the system of claim 5 is characterized in that:

Described first group of base station assigns given first operator; With

Described second base station assigns is given second operator.

7. the system of claim 5, it is characterized in that: on described first and second frequency bands, carry out in the communication between described first and second groups of base stations and the described network controller, described network controller has and is used for allowing the device that sends simultaneously and receive, and described base station does not have this kind device.

8. TDMA radio communications system that makes up the time-division Frequency Division Duplexing (FDD) comprises:

One first base station, it sends in first descending chain circuit frame on first carrier frequency, and is receiving on the second different carrier frequency, not having in first uplink frame of time-interleaving with described first descending chain circuit frame, and described system is characterized in that comprising:

One second base station, it sends in second descending chain circuit frame on described second carrier frequency, and on described first carrier frequency, with non-overlapping second uplink frame of described second descending chain circuit frame in receive; With

A network controller, it and described first and second base stations send synchronously and time alignment.

9. the system of claim 8 is characterized in that a symmetric pattern, and wherein descending chain circuit frame comprises and the as many time slot of uplink frame.

10. the system of claim 8 is characterized in that an asymmetric mode, and wherein descending chain circuit frame comprises a time slot with the different numbers of uplink frame.

11. the system of claim 8 is characterized in that a mobile radio terminal, it monitors the channel quality from the descending chain circuit frame of two base stations, is used for for call setup and switches the dynamic channel of carrying out mobile radio terminal control selecting.

12. the system of arbitrary claim of the claim 8-11 of front is characterized in that:

Described first base station belongs to one group and has the predetermined base station regularly that sends;

Described second base station belongs to one group of one second group of base station with described first group of base station synchronization and time alignment;

Described first frequency belongs to one first frequency band that is used by the base station in two groups of base stations; With

Described second frequency belongs to second frequency band that is used by the base station in two groups of base stations, and described second frequency band and described first frequency band do not have frequency overlap.

13. the system of claim 12 is characterized in that

Described first group of base station assigns given first operator; With

Described second group of base station assigns given second operator.

14. the system of claim 12, it is characterized in that: in described first and second groups of base stations be a side and described network control its carry out on described first and second frequency bands for the communication between the opposing party, described network controller has and is used for enabling the device that sends simultaneously and receive, and described base station does not then have this kind device.

15. the mobile radio terminal in the TDMA radio communications system of combination time-division and Frequency Division Duplexing (FDD), described system comprises:

First base station has first area of radio coverage, and is sending and receiving in first uplink frame of not having a time-interleaving with described first descending chain circuit frame on the second different carrier frequency at first descending chain circuit frame on first carrier frequency;

Second base station, has second area of radio coverage, and sending and on the second different carrier frequency, receiving at second descending chain circuit frame on first carrier frequency in second uplink frame of not having a time-interleaving with described second descending chain circuit frame, separate mutually on the geography on described second base station and the described first base station geography, in order to avoid disturb the reception of the radio terminal on other base stations from the transmission of a base station; With

Network controller is synchronously from the transmission of described first and second base stations, and sends with respect to transmission and the descending chain circuit frame of described second base station drift from first base station, and described mobile radio terminal is characterized in that:

A control unit is used for monitoring from channel quality on the descending chain circuit frame of two base stations and skew, to carry out the dynamic channel selection that mobile radio terminal is controlled for call setup and switching.

16. the mobile radio terminal in the TDMA radio communications system of combination time-division and Frequency Division Duplexing (FDD) comprises

First base station is sending in first descending chain circuit frame on first carrier frequency, with second, on the different carrier frequency with non-overlapping first uplink frame of described first descending chain circuit frame in receive;

Second base station sends in second descending chain circuit frame on second carrier frequency, and receives in first uplink frame of not having a time-interleaving with described first descending chain circuit frame second, on the different carrier frequency:

A network controller sends with described first and second base station synchronization and time alignment, and described mobile radio terminal is characterized in that:

A controller is used for monitoring the channel quality from the descending chain circuit frame of two base stations, so that carry out the dynamic channel selection that mobile radio terminal is controlled for call setup and switching.

17. the dynamic channel system of selection of the mobile radio terminal of a TDMA radio communications system that is used for making up the time-division Frequency Division Duplexing (FDD) comprises

One first base station has one first radio coverage area, sends in first descending chain circuit frame on first carrier frequency, and does not receive having in first uplink frame of time-interleaving with described first descending chain circuit frame second, on the different carrier frequency;

One second base station, has one second radio coverage area, on described carrier frequency, in second descending chain circuit frame, send, and do not receiving having in second uplink frame of time-interleaving on described second carrier frequency with described second descending chain circuit frame, described second radio coverage area part is overlapping with described first radio areas, and separate mutually with described first base station on the described second base station geography, disturb reception to avoid from the radio terminal on other base stations from the transmission of a base station; With

A network controller will be offset a descending chain circuit frame from the transmission of described second base station from the transmission of described first and second base stations and with respect to the transmission from described first base station synchronously, and described dynamic channel system of selection is characterized in that:

Monitor the channel quality of the descending chain circuit frame of two base stations;

Select a channel according to described channel quality; With

Described mobile radio terminal is locked onto on the channel of described selection.

18. the dynamic channel system of selection in mobile radio terminal in the TDMA radio communications system of combination time-division and Frequency Division Duplexing (FDD) comprises

One first base station is sending in first descending chain circuit frame on first carrier frequency, and does not receive having in first uplink frame of time-interleaving with described first descending chain circuit frame second, on the different carrier frequency;

One second base station sends in second descending chain circuit frame on described second carrier frequency, and is not receiving having in second uplink frame of time-interleaving with described second descending chain circuit frame on described first carrier frequency; With

The user network controller, from the transmission and the aligning of described first and second base stations, described dynamic channel system of selection is characterized in that synchronously:

Monitor the channel quality of the descending chain circuit frame of two base stations;

Select a channel according to described channel quality: and

Described mobile radio terminal is locked onto on the channel of described selection.

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